While revising a paper, I stumbled over two interesting LaTeX packages: `overpic` and `SIunits`. The former is a great way of "texifying" existing pictures. It shows you a grid as an overlay for the picture and allows you to position arbitrary LaTeX commands (such as short text description) to be positioned within this grid. This is great when the pictures are created in another application such as Inkscape or GIMP, but you still want to use the correct LaTeX fonts or mathematical symbols.

The latter package, `SIunits`, is the correct way of typesetting SI units. Of course, one could do this manually by using the math mode of TeX, but then one would have to ensure that the units are not shown in italics etc. Going with `SIunits` is easier: Just type `\square\metre`, for example, to get the unit of area. It is as simple as that.